Embed Image in Email Message in MPDF Using PHP - php

Question

Is there a way to embed an image in a message body in MPDF using php? Simply adding the HTML image tag as shown in the snippet below causes the actual tag to display in an e-mail.
$message = '<img src="Signature%20Card.jpg"/>';
Thank you for any ideas.
By the way, I am also sending an attached PDF. That part works fine though; only embedding the image does not work.
Below is the code for actually sending the e-mail:
$header = "From: ".$from_name." <".$from_mail.">\r\n";
$header .= "Reply-To: ".$replyto."\r\n";
$header .= "MIME-Version: 1.0\r\n";
$header .= "Content-Type: multipart/mixed; boundary=\"".$uid."\"\r\n\r\n";
$header .= "This is a multi-part message in MIME format.\r\n";
$header .= "--".$uid."\r\n";
$header .= "Content-type:text/plain; charset=iso-8859-1\r\n";
$header .= "Content-Transfer-Encoding: 7bit\r\n\r\n";
$header .= $message."\r\n\r\n";
$header .= "--".$uid."\r\n";
$header .= "Content-Type: application/pdf; name=\"".$filename."\"\r\n";
$header .= "Content-Transfer-Encoding: base64\r\n";
$header .= "Content-Disposition: attachment; filename=\"".$filename."\"\r\n\r\n";
$header .= $content."\r\n\r\n";
$header .= "--".$uid."--";
$is_sent = #mail($mailto, $subject, "", $header);

Answer 1

You need to get the $message variable into the body of the email for this to work properly. Currently the code is going into the header rather than the email message body. Change these lines by removing the middle line:
$header .= "Content-Transfer-Encoding: 7bit\r\n\r\n";
//$header .= $message."\r\n\r\n";
$header .= "--".$uid."\r\n";
And in the final line of code, place the $message variable into the mail command:
$is_sent = #mail($mailto, $subject, $message, $header);